Protoplanets and Protoplanetary Disks

Based on the existence of our solar system, and thousands of known exoplanets, we know that planets form. While theories have been developed to explain the demographics of these known planets, we have few direct constraints on the physical processes involved in planet formation. I will describe two approaches to constraining planet formation using observations of young stars and their circumstellar disks. These disks are the birth sites of planets, and constraining the fundamental properties of protoplanetary disks provides initial conditions for the processes of planet formation. I will describe new ALMA data that constrain disk masses, sizes, and other properties, in a typical region of star and planet formation. Even more direct constraints can be had by observing protoplanets that are still accreting matter. I will discuss new optical/infra-red imaging observations of recently discovered protoplanets residing in protoplanetary disks.